Haier HTR20-A, Руководство по обслуживанию

Страница: 23 / 31

23
SCL0 58 4.93 12.6K
ATV/DTV 59 0.008 54K
POWER 60 4.42 69K
DONAU LV WAKE UP 61 2.89 6.4K
DONAU LV RESET 62 4.9 12.25K
RMT-IN 63 0.85 133.6M
DVD_POWER 64 0.02 12.8K
2.Analysis of common path circuits
High frequency television signals, received via an antenna (or transmitted through
a cable TV system) to the input terminal of the high frequency tuner U101, are
processed for tuning and high frequency amplifying and mixing, then an analog IF
signal will go through the sound surface wave filter. Intermediate frequency signals will
be transmitted to (38) and (39) of N201(TMPA8873PSCNG). The mixed signals of
picture video signals output from (34) of N201.
3.Analysis of sound power amplifying circuits
Sound power amplifying circuits are composed of integrated circuits TDA1517NE
and peripheral components.TDA1517NE is an integrated electrical circuit .
Information introducing functions and testing data for TDA1517NE maintenance is
listed in Table 2.
Table 2
SYMBOL PIN DESCRIPTION
Working
Voltage (V)
Ground
Resistance (
Ω
)
-INV1
1
Non-inverting input 1
2.16 3.3M
SGND
2
Signal ground
0.004 0.3
Ω
SVRR 3 Supply voltage ripple rejection output 6.19 22.9K
Out 1
4
Output 1
76.16 1.3K
PGND
5
Power ground
0.003 0.1
Ω
OUT2
6
Output 2
6.19 1.3K
Vp 7 Supply voltage 12.9
∞
M/SS
8
Mute/standby switch input
10.9 21.95K
-INV2
9
Non-inverting input 2
2.162
∞
4.Analysis of vertical sync and vertical scan output circuits
The field sync signals segregated from compound sync signals are used to activate the
vertical frequency segregation system which commences when a set amount of vertical
sync pulse signals are tested. Of the sync pulse frequencies obtained from segregation,
some are transmitted to the vertical tooth wave generator. The vertical frequency tooth
wave, after geometric processing, is transmitted from (16) of N201 (TMPA8873PSCNG) to
(1) of vertical scan output IC N401 (LA78040).
Information introducing functions and testing data for LA78040 maintenance is listed in
Table 3. if a cylindrical color card is installed then a fluke III digital multimeter is used.
Table 3
SYMBOL PIN DESCRIPTION
Working
Voltage (V)
Ground
Resistance (
Ω
)
INV.IN 1 Inverting input
2.44 9.3K
Vcc 2 Supply voltage
26.3 14.2K